Re: Couple of suggestions

andrew_j_walker Apr 10, 2010

--- In find_orb@yahoogroups.com, Bill J Gray <pluto@...> wrote:
>
> Hi Andrew,
>
> > Firstly, elements.txt has a nice output of the most recent fit orbit
> > which includes keplerian and rectangular/cartesian coordinates. I'd like
> > to see this file get appended to when producing a series of
> > monte-carlo orbit (and please keep the heliocentric ecliptic elements
> > for the position/velocity coordinates!) so the net result is this
> > file will have 50, 100 or whatever clone data sets.
>
> That one was easy enough to do. Find_Orb will now create a file,
> 'state.txt', that is basically just a log of all the 'elements.txt'
> files created for a Monte Carlo run. Some parsing will doubtless be
> required to get that into Mercury or Swifter, though (dunno much about
> either program).
>
> > Secondly, there should be a way of getting a set of the planets'
> > position/velocity coordinates for whatever epoch is used for the
> > fitting. The main thing is that it has the exact same reference frame
> > as the output asteroid coordinates.
>
> That was a little trickier, but not much so. To get it, you'll need
> to add the line
>
> PLANET_STATES=y
>
> to the file 'environ.dat'. State vectors for all planets and the moon
> will then be shown in 'elements.txt'.
>
> The above is included in the 'in development' version, at
>
> http://www.gwi.net/~pluto/devel/find_orb.htm
>
> ...concerning which, more in my next message.
>
> -- Bill
>

Thanks for putting these in Bill, it's really appreciated! I'm
planning to do some runs on 2001 QR322 (a Neptune Trojan) to check
some of the work done in the Horner and Lykawka paper referred to
in the latest (No. 68) issue of Eko news at http://www.boulder.swri.edu/ekonews/issues/index.html

Both the Mercury and Swifter packages use the X Y Z
and VX VY VZ values on separate lines in the input files for
test particles so it's a simple matter to copy and paste
the output values from findorb.
These are at http://www.arm.ac.uk/~jec/home.html
and http://www.boulder.swri.edu/swifter/ for anyone curious,
however they take a bit of reading, compiling and setting up
to get working!

Andrew